I have been speaking French for the last twenty years and have been living every day in French for three years, and yet I am surprised by the French language all the time. Sometimes I get muddled in the specificity of terms because in English there is one word and in French there are numerous words for the same thing, depending on its shape or material. Take the word 'box' for example. In English, we just put a modifier in front of the word and we're good to go: shoe box, cardboard box, gift box, metal box, wooden box or just a box on a page. In French, there is a different word to learn for each one of these items. Let's take them one at a time.
shoe box: une boîte à chaussures
carboard box: un carton
gift box: un coffret cadeau
metal box: une boîte métallique
wooden box: une caisse en bois
box on a page: une case
I remember looking up box in the dictionary twenty years ago and I thought that the translation was boîte, but when I started using it to refer to a cardboard box that I had, I was corrected, making me aware of the complexity of it all!
Then there was the time that I was with my in-laws and I mentioned putting some fruit in a big bowl on the table. I just said un grand bol, thinking that they would get the picture. Their eyes became very wide and I could tell that they had no idea what I was talking about. "You know, a BIG bowl," I said, miming the shape of a big serving bowl. "Oh, you mean a saladier!" they exclaimed, finally getting it. Yes, but in this case there would not be a salad in it and actually I was talking about a bowl that would never have salad in it, but never mind, it's called a saladier whether you are using it to mix dough, display ornaments or whatever. A grand bol would be a bowl you would use for cereal, soup or maybe a large latte.
Not unrelated to the bowl incident is what to call the somewhat shallow bowls that we have. For Jean-Marc they are assiettes creuses (hollowed plates, or soup plates to be fair) whereas for me they are shallow bowls. Plate or bowl? There's no rim and the sides go up, so it's a bowl for me, but for Jean-Marc it's not what he drinks coffee out of, therefore it's a plate.
I can also recall a time when I mentioned the toilet. Now, I had always just assumed that the actual, physical fixture was called une toilette because we do ask where the toilettes are, after all. Jean-Marc did not understand what I meant; whatever I wanted to do with (or put in) the toilet just seemed impossible to him. I said "you know, the white thing you sit on in the toilettes" and that's when he informed me that this thing wasn't called a toilet. What? I've been getting this wrong for over twenty years? At the time, he couldn't even come up with the right word (it's une cuvette, in case you are wondering).
And then there's anything to do with education. I was on the phone with a training centre about a course I was interested in taking. I referred to it as a cours and the guy on the other end of the line was very quick to explain that it wasn't a course (that's only for diploma-granting institutions) but a formation or training session. I should have known this because back when I was an English teacher, I was a formatrice and not a professeur. I can see the difference between teacher and professor in English, but in French there is a whole sublist of possibilities, depending on where the teaching is happening. In elementary school, you can have a maître, maîtresse, institutrice or instituteur. In secondary and higher education you have a professeur and outside of that, there is also enseingant(e) and educateur/educatrice, as well as formateur/formatrice. The same thing goes for students, who are élèves (elementary and secondary), étudiants (post-secondary), stagiaires (continuing education or training), collégiens (junior high) or lycéens (senior high). Every time I have to talk about teachers and students I get all worried that I'll get it wrong!
Oh, and do you know the word for font or typeface? Police! Seriously, it's police.